package org.apache.lucene.document;
/**
 * Copyright 2006 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.apache.lucene.search.PhraseQuery; // for javadocs
import org.apache.lucene.search.spans.SpanQuery; // for javadocs
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.index.FieldInvertState;
import org.apache.lucene.util.StringHelper; // for javadocs
import org.apache.lucene.index.FieldInfo.IndexOptions;
import org.apache.lucene.index.FieldInvertState; // for javadocs

/**
 *
 *
 **/
public abstract class AbstractField implements Fieldable {

    protected String name = "body";
    protected boolean storeTermVector = false;
    protected boolean storeOffsetWithTermVector = false;
    protected boolean storePositionWithTermVector = false;
    protected boolean omitNorms = false;
    protected boolean isStored = false;
    protected boolean isIndexed = true;
    protected boolean isTokenized = true;
    protected boolean isBinary = false;
    protected boolean lazy = false;
    protected IndexOptions indexOptions = IndexOptions.DOCS_AND_FREQS_AND_POSITIONS;
    protected float boost = 1.0f;
    // the data object for all different kind of field values
    protected Object fieldsData = null;
    // pre-analyzed tokenStream for indexed fields
    protected TokenStream tokenStream;
    // length/offset for all primitive types
    protected int binaryLength;
    protected int binaryOffset;

    protected AbstractField() {
    }

    protected AbstractField(String name, Field.Store store, Field.Index index, Field.TermVector termVector) {
        if (name == null)
            throw new NullPointerException("name cannot be null");
        this.name = StringHelper.intern(name); // field names are interned

        this.isStored = store.isStored();
        this.isIndexed = index.isIndexed();
        this.isTokenized = index.isAnalyzed();
        this.omitNorms = index.omitNorms();

        this.isBinary = false;

        setStoreTermVector(termVector);
    }

    /** Sets the boost factor hits on this field.  This value will be
     * multiplied into the score of all hits on this this field of this
     * document.
     *
     * <p>The boost is multiplied by {@link org.apache.lucene.document.Document#getBoost()} of the document
     * containing this field.  If a document has multiple fields with the same
     * name, all such values are multiplied together.  This product is then
     * used to compute the norm factor for the field.  By
     * default, in the {@link
     * org.apache.lucene.search.Similarity#computeNorm(String,
     * FieldInvertState)} method, the boost value is multiplied
     * by the {@link
     * org.apache.lucene.search.Similarity#lengthNorm(String,
     * int)} and then
     * rounded by {@link org.apache.lucene.search.Similarity#encodeNormValue(float)} before it is stored in the
     * index.  One should attempt to ensure that this product does not overflow
     * the range of that encoding.
     *
     * @see org.apache.lucene.document.Document#setBoost(float)
     * @see org.apache.lucene.search.Similarity#computeNorm(String, FieldInvertState)
     * @see org.apache.lucene.search.Similarity#encodeNormValue(float)
     */
    public void setBoost(float boost) {
        this.boost = boost;
    }

    /** Returns the boost factor for hits for this field.
     *
     * <p>The default value is 1.0.
     *
     * <p>Note: this value is not stored directly with the document in the index.
     * Documents returned from {@link org.apache.lucene.index.IndexReader#document(int)} and
     * {@link org.apache.lucene.search.Searcher#doc(int)} may thus not have the same value present as when
     * this field was indexed.
     *
     * @see #setBoost(float)
     */
    public float getBoost() {
        return boost;
    }

    /** Returns the name of the field as an interned string.
     * For example "date", "title", "body", ...
     */
    public String name() {
        return name;
    }

    protected void setStoreTermVector(Field.TermVector termVector) {
        this.storeTermVector = termVector.isStored();
        this.storePositionWithTermVector = termVector.withPositions();
        this.storeOffsetWithTermVector = termVector.withOffsets();
    }

    /** True iff the value of the field is to be stored in the index for return
    with search hits.  It is an error for this to be true if a field is
    Reader-valued. */
    public final boolean isStored() {
        return isStored;
    }

    /** True iff the value of the field is to be indexed, so that it may be
    searched on. */
    public final boolean isIndexed() {
        return isIndexed;
    }

    /** True iff the value of the field should be tokenized as text prior to
    indexing.  Un-tokenized fields are indexed as a single word and may not be
    Reader-valued. */
    public final boolean isTokenized() {
        return isTokenized;
    }

    /** True iff the term or terms used to index this field are stored as a term
     *  vector, available from {@link org.apache.lucene.index.IndexReader#getTermFreqVector(int,String)}.
     *  These methods do not provide access to the original content of the field,
     *  only to terms used to index it. If the original content must be
     *  preserved, use the <code>stored</code> attribute instead.
     *
     * @see org.apache.lucene.index.IndexReader#getTermFreqVector(int, String)
     */
    public final boolean isTermVectorStored() {
        return storeTermVector;
    }

    /**
     * True iff terms are stored as term vector together with their offsets 
     * (start and end position in source text).
     */
    public boolean isStoreOffsetWithTermVector() {
        return storeOffsetWithTermVector;
    }

    /**
     * True iff terms are stored as term vector together with their token positions.
     */
    public boolean isStorePositionWithTermVector() {
        return storePositionWithTermVector;
    }

    /** True iff the value of the filed is stored as binary */
    public final boolean isBinary() {
        return isBinary;
    }

    /**
     * Return the raw byte[] for the binary field.  Note that
     * you must also call {@link #getBinaryLength} and {@link
     * #getBinaryOffset} to know which range of bytes in this
     * returned array belong to the field.
     * @return reference to the Field value as byte[].
     */
    public byte[] getBinaryValue() {
        return getBinaryValue(null);
    }

    public byte[] getBinaryValue(byte[] result) {
        if (isBinary || fieldsData instanceof byte[])
            return (byte[]) fieldsData;
        else
            return null;
    }

    /**
     * Returns length of byte[] segment that is used as value, if Field is not binary
     * returned value is undefined
     * @return length of byte[] segment that represents this Field value
     */
    public int getBinaryLength() {
        if (isBinary) {
            return binaryLength;
        } else if (fieldsData instanceof byte[])
            return ((byte[]) fieldsData).length;
        else
            return 0;
    }

    /**
     * Returns offset into byte[] segment that is used as value, if Field is not binary
     * returned value is undefined
     * @return index of the first character in byte[] segment that represents this Field value
     */
    public int getBinaryOffset() {
        return binaryOffset;
    }

    /** True if norms are omitted for this indexed field */
    public boolean getOmitNorms() {
        return omitNorms;
    }

    /** @deprecated use {@link #getIndexOptions()} instead. */
    @Deprecated
    public boolean getOmitTermFreqAndPositions() {
        return indexOptions == IndexOptions.DOCS_ONLY;
    }

    /** @see #setIndexOptions */
    public IndexOptions getIndexOptions() {
        return indexOptions;
    }

    /** Expert:
     *
     * If set, omit normalization factors associated with this indexed field.
     * This effectively disables indexing boosts and length normalization for this field.
     */
    public void setOmitNorms(boolean omitNorms) {
        this.omitNorms = omitNorms;
    }

    /** @deprecated use {@link #setIndexOptions(FieldInfo.IndexOptions)} instead. */
    @Deprecated
    public void setOmitTermFreqAndPositions(boolean omitTermFreqAndPositions) {
        if (omitTermFreqAndPositions) {
            indexOptions = IndexOptions.DOCS_ONLY;
        } else {
            indexOptions = IndexOptions.DOCS_AND_FREQS_AND_POSITIONS;
        }
    }

    /** Expert:
     *
     * If set, omit term freq, and optionally also positions and payloads from
     * postings for this field.
     *
     * <p><b>NOTE</b>: While this option reduces storage space
     * required in the index, it also means any query
     * requiring positional information, such as {@link
     * PhraseQuery} or {@link SpanQuery} subclasses will
     * silently fail to find results.
     */
    public void setIndexOptions(IndexOptions indexOptions) {
        this.indexOptions = indexOptions;
    }

    public boolean isLazy() {
        return lazy;
    }

    /** Prints a Field for human consumption. */
    @Override
    public final String toString() {
        StringBuilder result = new StringBuilder();
        if (isStored) {
            result.append("stored");
        }
        if (isIndexed) {
            if (result.length() > 0)
                result.append(",");
            result.append("indexed");
        }
        if (isTokenized) {
            if (result.length() > 0)
                result.append(",");
            result.append("tokenized");
        }
        if (storeTermVector) {
            if (result.length() > 0)
                result.append(",");
            result.append("termVector");
        }
        if (storeOffsetWithTermVector) {
            if (result.length() > 0)
                result.append(",");
            result.append("termVectorOffsets");
        }
        if (storePositionWithTermVector) {
            if (result.length() > 0)
                result.append(",");
            result.append("termVectorPosition");
        }
        if (isBinary) {
            if (result.length() > 0)
                result.append(",");
            result.append("binary");
        }
        if (omitNorms) {
            result.append(",omitNorms");
        }
        if (indexOptions != IndexOptions.DOCS_AND_FREQS_AND_POSITIONS) {
            result.append(",indexOptions=");
            result.append(indexOptions);
        }
        if (lazy) {
            result.append(",lazy");
        }
        result.append('<');
        result.append(name);
        result.append(':');

        if (fieldsData != null && lazy == false) {
            result.append(fieldsData);
        }

        result.append('>');
        return result.toString();
    }
}
